2015 R1 case study

//2015 R1 case study

2015 R1 case study

When a new bike comes out that is born from a clean sheet of paper – there has to be a lot of excitement in the motorcycling community.

Rather than redesign a new bike every two or three years (a massively expensive undertaking) why not improve the electronics and put existing technology on the bike that is in use and field tested? Much cheaper and far more ROI for the OEM’s.

Enter the 2015 R1 and the ever evolving electronics race for sport bikes.

The case study bike belongs to Jeff Viets of www.vietsperformance.com. He took delivery of it over the weekend from Mach 1 in Vallejo and rode it home. His initial impressions were based on his many years as an instructor with Keigwin’s at the track and were drawn against his perfect for him 07 R1.

“It’s not compliant and the front end rides tall BUT it turns in great, is very agile and brakes really well.”

So, for all of you new R1 owners that want to blast off into the distance on your new ride for the first ever ride – don’t. You have some work to do based on the findings from the chassis review and subsequent changes made to the bike.



The throttle housing position change seemed to me to be an absolute immediate must. When you look at the photo’s of the right bar, the cables run underneath the master cylinder and there’s a significant amount of tension on the cables as they don’t line up evenly with the housing based on the routing on top of the frame.

Everything seems to be so much better once the cables run on top of the master cylinder.


 wanted to move the master cylinder down but the wiring is in the way from the kill switch and the brake line is very close to the upper fork outer tube. Don’t try to move the brake line as there’s a silver bolt in the top of the banjo fitting to stop you moving the line at all and that bolt hits a cast arm in the master cylinder to stop rotation. So you need to make your own choice on a new upper line to allow you to get the angle and reach of the master cylinder to meet your ergonomic needs.

The handlebars are bolted in place so you need to make a personal choice on removing the bolt if you want to experiment with bar position to make your wrists and hands line up naturally to relieve tension and arm fatigue. If stock works, leave the bolt in. If the bolt out gives you way less fatigue, make a choice.


Chassis setting from the factory taken on the bike:

Fork height +7mm, preload 9 turns in from full soft, rebound 5 clicks out from maximum, compression 17 clicks out from maximum.

Shock height +3mm ride height, preload 5 threads showing, low speed compression 9 clicks out from maximum, high speed compression 3 turns out from maximum, rebound 13 clicks out from maximum.

Jeff weighs in at 185lbs/84kg without gear and I took the following data points

Forks extended 130mm measuring from the joint of the dust seal with the outer tube to the bottom of the chrome tube

Fork travel 120mm so bottom out is 10mm up from the axle casting and I’d mark it at 15mm to be conservative

Static sag/bike under its own weight 120mm

Rider on board 102mm

Total sag 32mm

Rear shock

Extended from the axle casting to the center of the rear turn signal 530

Static sag/bike under its own weight 525mm

Rider on board 495mm

Total sag 35mm

Based on Jeff’s comments, validation of this feelings as the bike has more sag in the rear therefore a rear bias in pitch.

Chassis changes:

Fork height +7mm, preload full soft, rebound 27 clicks out from maximum, compression 25 clicks out from maximum.

Shock height +3mm ride height, preload 5 threads showing, low speed compression 8 clicks out from maximum, high speed compression 3 turns out from maximum, rebound 10 clicks out from maximum (I have a feeling 9 will be better).

Next up? Ride Friday lunch time to get the suspension oil hot and run another series of settings to get the bike to handle how Jeff wants it to work for him.

2015 R1 street/road dial in, Ambient temps mid 70F, Road temp 100-110F average

With the suspension set previously at Jeff’s home, it was time to get on the road and see how the bike performed with toasty hot suspension fluids and tires. In addition the RS10 Bridgestone OEM tires were a complete unknown so we needed to get some data points on the tire as well.  Tire pressure started at 40psi rear and 36psi front cold set in the garage.

Perfect day and a 2 for 1 special between suspension and tires!

The first ride was a 30 mile warm up ride between freeway and a local favorite, Lucas Valley Road. It was very evident that the front with all settings at full soft was still too hard as the wheel lifted up over bumps and on a few occasions I could see daylight under the front wheel.

Once the run was completed I checked tire temps and they were colder than they were on the driveway sitting in the sun:- 110F front and 115F rear. I immediately changed the tire pressure to 35psi hot rear and 32psi hot front in an attempt to

1. Get heat into the tire

2. Make the tire do more suspension work as obviously the carcass was very firm from visual observations.

Closer inspection of the bike found there was not enough chain free play so that was changed as well by 1.75 turns inwards to increase free play.


On the second ride focused on Lucas Valley exclusively due to it’s up and down elevation changes, fast and slow turns and different cambered corners, Jeff had a lot to pay attention to between the stiff forks, revised tire pressure and correct chain free play.

“It had been years since I’d ridden on the street – the last real street ride I can recall was bringing my 2007 R1 home from the dealership! Dave and I had a gorgeous afternoon on one of my favorite stretches of road – Lucas Valley Road to Nicasio. I’ve ridden West Marin thousands of times over the years, but it had been a while – and on a brand new bike it took some getting used to. Dave had me traverse several sections repeatedly which helped me focus on re-learning the road and paying attention to how his changes improved the bike.”

On his return I paid close attention to the amount of travel used in the front fork and at this point with moderate riding, fork travel was at 50% of known limits given the 20mm bottom out.

In response to Jeff’s comments, the front forks were left alone in all aspects and the rear shock had the following changes made:


– rebound 8-6 clicks out to slow it down

– low speed compression 8-10 clicks out

The third ride was essentially a downhill ride with much more weight transfer onto the front end and 100% focus on braking. I wanted to see how much more travel Jeff would use in the forks.

“With every change he made, Dave got the bike working better and better, but on the downhill section where I was getting into the brakes and loading the front end a bit more was problematic. I had read in the Roadracing World test they noted at the track they felt the ABS had the bike running wide, until they installed the track-only ECU with different ABS settings. Initially, I thought that might have something to do with the struggles I was having holding my line in the downhill switchbacks, but I wasn’t going that fast. So I think it’s just the brick-like stiffness of the front that we need to sort further.”

On return he had used another 10mm of stroke, a lot less than expected.

I checked rear tire temperatures again when he returned and the rear tire temps had not increased above 120F so we set the front at 32psi hot and the rear at 30psi hot.


The 4th ride was on a fast flowing section of road with wide open visibility which allowed the R1 to travel faster on the road and therefore generate much more heat in the tires and suspension.  The tires hit the 145F mark, so we knew that we had a good pressure for faster riding but not a good number for more technical roads. That means we have to do some more road testing with hotter temps and track testing in the very near future to see how the pressure changes with the duress of a fast track – Thunderhill

As part of this final ride Jeff braked really hard in a straight line to try to fully collapse the forks, but on analysis based on a 20mm bottom out above the axle casting, he was still considerably short of bottom out at full soft on preload, rebound and compression. Indeed rebound was still too slow so that guides the engineering analysis to oil viscosity and rebound valving.

In following him through the fast turns I could see the shock was rebounding too fast upsetting the chassis, so it was changed to 4 clicks out.

At the end of the test period, these were Jeff’s thoughts:

“The new R1 is an absolute blast to ride – once we loosened the chain to allow the shock to work properly and got tire pressures dialed in I was really starting to enjoy it. The rear now works terrific and I don’t see the need to fit an Ohlins shock anytime soon based on just how good it feels in all aspects. The front is good – the bike steers like a 600 and feels half its size. However, it is a brick… it feels like it is set up for race-winning lap times at the track – something Tyler O’Hara, a local racer did quite well with a stock 2015 R1 in the first AFM round at Buttonwillow a few weeks ago – winning Open Production with only bodywork and race tires – he didn’t even change the stock gearing. But I’m not Tyler O’Hara, and this bike is going to see some street miles. So Dave is going to dig into the front forks and see what it will take to make them right. ”


–       forks too stiff based on average travel used, need to investigate why

–       shock rebound damping too light, 4 clicks out being optimal on the final ride

–       RS10 carcass very stiff, lower than expected pressures needed to get heat in the tire and need to test higher pressures to validate this.

By |2018-01-27T19:04:46+00:00December 26th, 2017|Categories: Reviews|0 Comments

About the Author:

Journalist, published author, 1-1 coach and mentor, video presenter

Leave A Comment